Method and apparatus for examining the compression and the ignition of internal combustion engines by means of a small illuminating tube



Dec. 13, 1938. J KANDYBA q ,';.2,139,828 METHOD AND APPARATUS FOREXAMINING THE COMPRESSION AND-THE IGNITION OF INTERNAL COMBUSTIONENGINES BY MEANS OF A SMALL ILLUMINATING- TUBE Filed July 27, 1937 Invefitor": M

Patented Dec. 13, 1938 UNITED STATES PATENT} OFFICE METHOD AND APPARATUSFOR. EXAMINING THE COMPRESSION AND THE IGNITION 0F 1 INTERNALCOLIBUSTION ENGINES BY MEANS OF A SMALL ILLUMINATING TUBE JuliusKandyba, Berlin, Germany Application July 27, 1937, Serial No. 155,988

- In Germany August 6, 1936 4 Claims.

The invention relates to a method and apparatus for examining thecompression and the ignition of internal combustion'engines-on sparkingplugs, caps of such plugs, cable shoes ignition cables or distributorsby means'of a small' illuminating tube, and it is based on the novelobservation that a small'illuminating tube indi-I charging gap, and thatthe energy transmitted from the igniting circuit to the smallilluminating tube, by means of the auxiliary discharging gap or anyother coupling element, is dimensioned so that, when the ignition andcompression are normal, a lighting up of the illuminating tube of acertain average brightness occurs. If changes occur in the compression,and if disturbances happen in the ignition plant or on the sparkingplug, the light becomes weaker or stronger, and if there is nocompression and the ignition works perfectly the light is very feeble ordoes not exist at all.

As device for carrying out this new method a device may serve, in whichthe small illuminating tube is connected for instance by means of aninsulated auxiliary electrode through the auxiliary discharging gap orthe like to one of the two sparking plug electrodes preferablyunipolarily and is arranged in or on a protecting cap adapted to beplaced over the sparking plug.

An embodiment of the invention is illustrated, by way of example, in theaccompanying drawing in which Fig. 1 is a vertical longitudinal sectionthrough a device for fitting on a sparking plug.

Figs. 2 to 5 are diagrammatic views showing different circuitarrangements.

Fig. 1 shows in section the small illuminating tube connectedunipolarily to the ignition circuit, i. e. to one of the sparking plugelectrodes through the intermediary of an auxiliary discharging gap.

a designates a protecting cap adapted to be placed over the sparkingplug and having a horizontal transverse channel b for the ignitioncable. The ignition cable is pierced by the point of the vertical,electrically conducting carrier screw 0, when this screw is screwed in;the central longitudinal bore of the carrier screw serves foraccommodating the screw spindle of the sparking. plug. A ball d and. aband spring e serve '-as holding device and for establishing a goodcontact with the sparking plug electrode. An auxiliary electrode 1 isheld by an insulating disc'g, a metal disc h and the carrier screw 0.The-discs g and'h have at the pointbelow the lower bent off end of theauxiliary electrode f small apertures t,'t' which represent theauxiliary discharging gap The upper end of the auxiliary electrode f isin connection with the upper metallic coating 2' of thesmallilluminating tube k. The stopper Z, also of insulating material, carriesthe observation tube m and presses a spiral spring n against the lower.metallic coating 0, so that'the illuminating, tube is lifted andsecurely held. A number plate ,9 for the corresponding cylinder ismounted in the upper portion of the cap. The distance of the auxiliaryelectrode f from the metal disc h is determined by the thickness of theinsulating disc 9 and is such that the illuminating tube lights up inthe cylinder only with average. brightness when the compression andignition are normal; the illuminating tube thereby becomes verysensitive, so that, when disturbances occur in the compression andignition numerous graduations of the brightness in downward and upwarddirection are obtained, said graduations being further indicated for theobserver by broader and narrower light strips. If, for instance, thecompression continually decreases owing to losses on pistons, packingsand 'the like, the transition-resistance for thesparking plug in thecylinder decreases also continually, auxiliary discharging and lightingup becoming consequently continually feebler. The same is the case, ifthe sparking plug is sooted, or if the distance between the sparkingplug electrodes is too small. If there is no compression theilluminating tube It lights up only very weakly notwithstanding fullignition tension, and, when disturbances in ignition occur, the lightingup of the illuminating tube may temporarily or completely cease. In thismanner the service conditions of the motor and of every single cylinderis supervised.

The employment of the auxiliary discharging gap presents further thefollowing advantage: Before the ignition tension has attained itsmaximum value, a quiet auxiliary discharging takes place between metalplate It and auxiliary electrode I through the apertures t, t of the twodiscs mentioned above; owing to distributed inductivity and capacity andowing to the small dimensions high frequency oscillations are producedwhich,

acting upon the small illuminating tube 10, superimpose the breakdownvoltage, so that the ignition sparkis, now more easily produced owing to6 increase of voltage, and the device serves at the same time also asignition exciter.

Figs. 2 to 5 illustrate several examples of connection with employmentof different switching elements, for instance condensers, for otherwisecoupling the illuminating tube with the ignition circuit u, in order tobe able to adjust also at high and low compression motors theilluminatingtube k to average brightness at normal compression andignition. As shown in Fig. 2 the illuminating tube k has at the lowerend a condenser r as counterweight, and its upper end isseries-connected with the condenser r through the intermediary of anauxiliary discharging gap, indicated by the arrow s. By this arrangementthe, control range of the illuminating tube canbe enlarged from -20atmospheres compression for instance for motors of sport cars. I Alsothe arrangement illustrated in Fig. 3 is adapted for a large indicatingrange. The arrangement shown in Fig. 4 is adapted for low compressingmotors, and that in Fig. 5 for the maximum efficiency from 20-18atmospheres compression for a high compressing motor. I 1

I claim':---

1. A devicefor-testing the compression and ignition of internalcombustion engines, comprising in combination with a sparking plug, aprotecting cap of insulating material and adapted to be placed over andsecured on said sparking plug 35 having a hollow'space in its wall, acarrier screw of conductive material in said protecting cap and having abore for accommodating the screw spindle of the sparking plug, a metalplate and an insulating plate on said metal plate having each one anaperture forming the auxiliary discharging gap, an auxiliary electrodeabove said apertures in said metal plate and in said insulating plate,and an illuminating tube in said hollow space or said protecting cap,and means for connecting one pole of said illuminating tube to saidauxiliary electrode.

I 2. A device as specified in claim 1, in which the protecting cap isnumbered according to the s'parkingplug on which it is fitted and theauxiliary electrode and metal plate cooperate in producing highfrequency oscillations-acting on the breakdown voltage to inciteignition.

3. A method for testing the compression and ignition of internalcombustion engines by means of an illuminating lamp, consisting inconnecting the illuminating tube unipolarily in the ignition circuitover an auxiliary discharge gap, supplying a regulated amount of energyto said tube to induce illumination of medium intensity under normalengine ignition and compression conditions but fluctuationsin intensityin the event of disturbances in either of said conditions.

4. A device for testing the compression and ignition of internalcombustion engines, comprising in combination with a sparking plug, aprotecting cap of insulating material adapted to be slipped onto saidsparking plug and having a recess, an illuminating tube i'nsaid recess,elements in said cap forming an auxiliary discharging gap, an electrodeleading from said gap to one end of said tube, and means pressing saidtube against said electrode. a

, JULIUS KANDYBA,

